Rimonabant – A Way to Tackle Addiction?

The mechanisms that the brain uses when it gets addicted to something are slowly being unearthed. So far, it is far from being totally understood but there is substantial evidence that this process needs the endocannabinoid system.

Cannabis use disorders are becoming more common and more frequently diagnosed. It was not believed in the past that cannabis was addictive in the way that hard drugs like heroin are; recent evidence has shown that the same addictive mechanisms are employed. Because this seems to involve the endocannabinoid system, it is an ideal target for therapies for cannabis use disorders and the abuse of other drugs.

Cannabinoids and Addiction

Preliminary evidence has suggested that cannabinoids can be used to modulate the reward felt from addictive drugs and that they can be used to help withdrawal from drugs. Although cannabis use disorders are more common than most other common drug abuse disorders, it has received relatively little attention.

This study aimed to build robust animal models of self-administered THC (the psychoactive constituent of cannabis) to study the effects of rimonabant, a cannabinoid antagonist (a chemical that alters or blocks how a receptor works). The authors believe that it might be useful for treating cannabinoid dependence.

Cannabis Use Disorders Are Increasing with Little Help

An estimated 10% of the American population has a cannabis use disorder. This is 4 times that of cocaine and appears to be growing. While cannabis is a relatively safe drug, abuse of the drug is related to mental health and physical disorders. Currently, therapy is lagging behind that of other illicit and legal drugs, partly because it was not recognized as a disorder for a long time. Effective therapies are rare and none is drugs mediated.

Although cannabis can be used to help come off other drugs, there are no known drugs that can help with coming off cannabis. Withdrawal symptoms are relatively mild but they are present, and the social aspects of cannabis use cessation make it difficult to quit long-term.

Cannabinoid Receptor Antagonists Could Prove Useful in Therapy

The cannabinoid rimonabant blocks the interaction of other cannabinoids with the CB1 receptor, the receptor that is most present in the brain and is responsible for the psychoactive effects of cannabis when triggered. By blocking this receptor in squirrel monkeys with rimonabant, the authors of self-administered able to study how cannabis seeking behaviour changed.

The monkeys were trained to self-administer cannabinoids and then had the cannabinoids withdrawn. When they were reintroduced, the squirrel monkeys that had been administered rimonabant did not seek out more cannabinoids whereas the others did.

By preventing cannabis seeking behaviours, cannabis receptor antagonists like rimonabant could be administered to people who need to quit cannabis. It is a relatively safe and tolerable drug, which adds to the appeal.

The rising tide of cannabis use disorders presents a challenge to therapists and legislators. The use of cannabis receptor antagonists, which block THC interaction with cannabinoid receptors, is one potential method for decreasing both the reward from cannabis and cannabinoids and reducing the “need” or desire for more of the drug. More research is needed.

Registered with the British Psychological Society, breaking the taboo on mental health issues is one of the driving forces in Jonathan's life. His background in biomedicine gives him additional understanding of the factors that work together to influence the human condition.